'It’s not if, it’s when': The deadly pig disease spreading around the world

Ott Saareväli, the owner of a pig farm in Lääne county in Estonia, is starting all over again. In September last year, government vets diagnosed an outbreak of African swine fever (ASF) in a section of the farm where pregnant sows are held ahead of farrowing. It made no difference that the outbreak had been limited to one area – all seven thousand of his pigs would have to be slaughtered immediately.

“We have the strictest biosecurity measures here, and still no one is quite sure how the disease got in – it may have been a truck that wasn’t washed properly after visiting an infected farm,” says Saareväli. “But if you find just one pig, then everything has to go.”

In the wake of the diagnosis, the outhouse used for storing dead pigs was piled high with more than 200 carcasses from the affected section, some of which had been rotting for more than a week. Many of the carcasses had burst open, spilling out dozens of dead piglets. They would all have to be removed by hand, which even some of Saareväli’s most experienced farmhands could not bring themselves to do. The thousands of remaining, healthy pigs would be loaded into special lorries where they would be gassed. The killing process took a little over a week.

“It was emotionally very difficult for everyone,” says Saareväli. “The worst thing was the silence after the last pig was gassed. Pig farms are noisy places, but here it was completely silent.”

This is not the first time Europe has been struck by ASF. In 1957, it was introduced into Portugal, reportedly after infected airline food was fed as swill to pigs near Lisbon airport. The disease spread to Spain and France and took until the 1990s to eradicate through concerted surveillance and culling. In southern Spain, where ticks acted as an additional reservoir, old-fashioned farm buildings were destroyed and replaced with modern facilities to keep ticks out. “There was a major effort to eradicate it,” says Linda Dixon, a cell biologist who works on ASF at the UK’s Pirbright Institute.

This time the spread has been far more rapid despite considerable biosecurity efforts. The current outbreak in central and eastern Europe began in January 2014, when cases were first reported in Lithuania, swiftly followed by outbreaks in Poland in February, and in Latvia and Estonia in June and September that year.

Cases were also confirmed in the east of the Czech Republic in June 2017, and in Romania and Hungary earlier this year. More outbreaks have also been reported in Russia, Ukraine and Moldova. In recent weeks outbreaks have been reported in China, home of more than half the world’s pigs, which produces twice as much pork as the EU, and five times more than the United States.

In Germany, farmers have called for a cull of 70% of the wild boar population, which is thought to be hundreds of thousands strong. “High populations of wild boar made the controls more difficult and once you have so many boar it’s difficult to reduce the number because they just keep reproducing,” says Dixon. “They’re very successful animals with a range right across Asia and Europe. They can swim as well.”

In Denmark, a fence is planned along the border with Germany to prevent the migration of wild boars. “If African swine fever were to occur in Denmark the third country export markets would close immediately, and the inter-community trade within the EU would be affected,” says Sisse Berg Wulff, a vet at the Danish Veterinary and Food Administration.

She adds that it is only a matter of time until the disease reaches Denmark, a major pork exporter. Denmark’s National Veterinary Institute has estimated that an outbreak could cost the country up to 10bn Danish crowns (£1.2bn).

Ott Saareväli, the owner of a pig farm in Lääne county in Estonia, is starting all over again. In September last year, government vets diagnosed an outbreak of African swine fever (ASF) in a section of the farm where pregnant sows are held ahead of farrowing. It made no difference that the outbreak had been limited to one area – all seven thousand of his pigs would have to be slaughtered immediately.

“We have the strictest biosecurity measures here, and still no one is quite sure how the disease got in – it may have been a truck that wasn’t washed properly after visiting an infected farm,” says Saareväli. “But if you find just one pig, then everything has to go.”

In the wake of the diagnosis, the outhouse used for storing dead pigs was piled high with more than 200 carcasses from the affected section, some of which had been rotting for more than a week. Many of the carcasses had burst open, spilling out dozens of dead piglets. They would all have to be removed by hand, which even some of Saareväli’s most experienced farmhands could not bring themselves to do. The thousands of remaining, healthy pigs would be loaded into special lorries where they would be gassed. The killing process took a little over a week.

“It was emotionally very difficult for everyone,” says Saareväli. “The worst thing was the silence after the last pig was gassed. Pig farms are noisy places, but here it was completely silent.”

This is not the first time Europe has been struck by ASF. In 1957, it was introduced into Portugal, reportedly after infected airline food was fed as swill to pigs near Lisbon airport. The disease spread to Spain and France and took until the 1990s to eradicate through concerted surveillance and culling. In southern Spain, where ticks acted as an additional reservoir, old-fashioned farm buildings were destroyed and replaced with modern facilities to keep ticks out. “There was a major effort to eradicate it,” says Linda Dixon, a cell biologist who works on ASF at the UK’s Pirbright Institute.

This time the spread has been far more rapid despite considerable biosecurity efforts. The current outbreak in central and eastern Europe began in January 2014, when cases were first reported in Lithuania, swiftly followed by outbreaks in Poland in February, and in Latvia and Estonia in June and September that year.

Cases were also confirmed in the east of the Czech Republic in June 2017, and in Romania and Hungary earlier this year. More outbreaks have also been reported in Russia, Ukraine and Moldova. In recent weeks outbreaks have been reported in China, home of more than half the world’s pigs, which produces twice as much pork as the EU, and five times more than the United States.

In Germany, farmers have called for a cull of 70% of the wild boar population, which is thought to be hundreds of thousands strong. “High populations of wild boar made the controls more difficult and once you have so many boar it’s difficult to reduce the number because they just keep reproducing,” says Dixon. “They’re very successful animals with a range right across Asia and Europe. They can swim as well.”

In Denmark, a fence is planned along the border with Germany to prevent the migration of wild boars. “If African swine fever were to occur in Denmark the third country export markets would close immediately, and the inter-community trade within the EU would be affected,” says Sisse Berg Wulff, a vet at the Danish Veterinary and Food Administration.

She adds that it is only a matter of time until the disease reaches Denmark, a major pork exporter. Denmark’s National Veterinary Institute has estimated that an outbreak could cost the country up to 10bn Danish crowns (£1.2bn).